The field of art to which this invention pertains is synthetic resins made from phenols and a reactant containing epoxy groups.
It is well known in the art to prepare higher molecular weight polyhydroxypolyether resins by reacting a vicinal epoxy-containing compound with a phenolic hydroxyl-containing compound in the presence of such catalysts as organic phosphines, tertiary amines, and quaternary phosphonium, or ammonium compounds. Such reactions are generally conducted in bulk in the absence of a solvent at temperatures of 150.degree. C. to 250.degree. C. or higher. Due to the exothermic reaction of the epoxy group and phenolic group, the rate of reaction and increase in temperature is sometimes difficult to control. High temperatures are also required to keep the reactants in a fluid state and to keep the reaction product fluid so that it can be removed from the reactor. Such high temperatures can result in dark colored products and undesirable side reactions which can cause branching and wide distributions in molecular weights. The reaction can also continue during the long cool down time leading to higher molecular weights than desired and to stability problems. The products obtained by the bulk reaction must be pulverized or flaked in order to be useful.